Transfusion-related morbidity is a major problem in thalassemia, researchers from the American Centers for Disease Control and Prevention (CDC) conclude in a new report.
Elliott Vichinsky, MD, and colleagues at the CDC Thalassemia Blood Safety Network evaluated data on 407 patients, including 327 chronically transfused (>8 times/year) and 80 intermittently transfused (<8 times/year) patients. Hemosiderosis occurred in both patient groups and correlated with transfusion history. The average ferritin (m/L) in each group, respectively, was 2261 and 689.
Multiple organ dysfunction was common in the population, including cardiac disease (13%), gonadal failure (17%), growth hormone deficiency (8%), hypothyroidism (8%), hypoparathyroidism (1.2%), diabetes (10%), and thrombotic events (5.4%). And 45% of the population was splenectomized.
Transfusion-associated infections included 58 cases of hepatitis C and four cases of HIV. The researchers found recent cases of bacteremia, malaria, and babesiosis. Also, 21% of chronically transfused patients and 13% of intermittently transfused patients developed an alloantibody, with 45% of alloimmunized patients having multiple antibodies.
The investigators found alloimmunization in 31% of splenectomized patients vs 10% of non-splenectomized patients (P <0.0001). The alloimmunization prevalence rose from 10% in young children to 54% in older patients. The average units transfused in patients with alloantibodies was 215 +/-104 vs 126 +/-92 in patients without alloantibodies (P <0.0001).
Autoantibodies occurred in 6.5% of the population and increased with age and splenectomy. Alloimmunization increased the risk of autoantibodies: 26% of patients with an alloantibody had an autoantibody, whereas only 2% of patients without alloantibodies had an autoantibody (P <0.0001). Overall, 81% of patients with an autoantibody had an alloantibody.